A small hole of area of cross-section $2{ \mathrm{mm}}^2$ is present near the bottom of a fully filled open tank of height 2 m. Taking $\mathrm{g}=10 \mathrm{m}/{\mathrm{s}}^2$ the rate of flow of water through the open hole would be nearly

• A

  $6.4\times {10}^{-6}{ \mathrm{m}}^3/\mathrm{s}$

• B

  $12.6\times {10}^{-6}{ \mathrm{m}}^3/\mathrm{s}$

• C

  $8.9\times {10}^{-6}{ \mathrm{m}}^3/\mathrm{s}$

• D

  $2.23\times {10}^{-6}{ \mathrm{m}}^3/\mathrm{s}$